Tip-resistant pad for use with a heavy article and seismic isolation structure incorporating same

ABSTRACT

In a gravestone structure including a foundation stone ( 2 ) and a headstone ( 3 ), four tip-resistant pads ( 4 ) and as many pressure plates ( 5 ) as the pads ( 4 ) are interposed between the foundation stone ( 2 ) and the headstone ( 3 ). Each of the tip-resistant pads ( 4 ) includes a sheet elastic body ( 6 ) and a point support member ( 7 ) embedded in an eccentric position in the sheet elastic body ( 6 ). The sheet elastic body ( 6 ) is formed of a transparent, flexible and elastic gel material that absorbs vibrations of the headstone ( 3 ). The point support member ( 7 ) is formed of a metal or resin harder than the gel elastic material and undergoes plastic deformation under the load of the headstone ( 3 ). In order to render the gravestone structure ( 1 ) seismically isolated, four tip-resistant pads ( 4 ) are arranged on the top surface of the foundation stone ( 2 ) with the point support members ( 7 ) oriented inward of the foundation stone ( 2 ).

FIELD OF THE INVENTION

The present invention relates to tip-resistant pads for preventing heavy articles from tipping over or falling down due to earthquakes. The present invention additionally relates to seismic isolation structures using these pads.

TECHNICAL BACKGROUND

Conventionally, tip-resistant pads, such as the one shown in FIG. 7, have been known. This tip-resistant pad 51 includes a sheet elastic body 52 made of a flexible material that absorbs the vibration of a heavy article and a point support member 53 capable of plastic deformation under the load of the heavy article. The point support member 53 is embedded and held at the center of the sheet elastic body 52 via a ring 54 For example, in a gravestone structure 55 shown in FIG. 8, four tip-resistant pads 51 are interposed between a foundation stone or base 56 and a headstone 57 so as to prevent the tipping over or falling down of the heavy article or headstone 57 during or due to an earthquake.

Japanese Patent No. 4238277 describes a tip-resistant sheet comprising an elastic body 52 formed in the shape of a sheet and made of a flexible and elastic material, such as polyurethane rubber, butyl rubber, acrylic rubber, silicon rubber, natural rubber, or any other suitable material. This tip-resistant sheet further comprises a point support member 53 in the shape of a sphere made of a relatively hard material that is capable of undergoing plastic deformation, such as tin, solder, lead, silver, plastic, or any other suitable material, so that the sheet elastic body 52 is not crushed under the load of a heavy article.

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

According to the conventional tip-resistant pad 51, as the relatively hard support member 53 is held at the center of the sheet elastic body 52, which is softer than the point support member 53, the effective area of the sheet elastic body 52 that absorbs vibrations is decreased. For example, if four tip-resistance pads 51 are used as shown in FIG. 8, approximately one quarter (¼) of the area of each sheet elastic body 52 falls within an inner region of the foundation stone 56 (i.e., the region within the square defined by connecting the point support members 53). This reduces the effective area of the sheet elastic body 52, thus adversely affecting the ability of the tip-resistant pad to prevent the heavy article thereon from tipping over.

In view of the above-identified problems, an important object of the present invention is to provide a tip-resistant pad with a sheet elastic body that has an increased effective area for an increased ability to prevent heavy articles from tipping over or falling down. Another important object of the present invention is to provide a seismic isolation structure using this tip-resistant pad.

Means to Solve the Problem

To solve the foregoing problem, the present invention provides a tip-resistant pad for being interposed between a foundation and a heavy article to prevent the heavy article from tipping over due to an earthquake. The tip-resistant pad comprises: a sheet elastic body made of a flexible material for absorbing vibrations of the heavy article and a point support member made of a material that is harder than the sheet elastic body and undergoes plastic deformation under the load of the heavy article. In this tip-resistant pad, the point support member is held in an off-center position or a position deviated from a center of the sheet elastic body.

In one aspect of the present invention, the point support member of the tip-resistant pad is embedded in a corner of the sheet elastic body.

In another aspect of the present invention, the point support member is embedded in the sheet elastic body with a portion of the support member exposed.

In still another aspect of the present invention, the sheet elastic body of the tip-resistant pad is formed of a transparent and elastic gel material.

In yet another aspect of the present invention, the sheet elastic body is provided with an adhesive layer on top and bottom surfaces thereof.

In one embodiment, the sheet elastic body is provided with an adhesive layer on top and bottom surfaces thereof.

The present invention is also directed to a structure including a foundation, a heavy article, and a plurality of tip-resistant pads interposed between the foundation and the heavy article to prevent the heavy article to tip over due to an earthquake. In this structure, each of the plurality of tip-resistant pads comprises a sheet elastic body made of a flexible material for absorbing vibrations of the heavy article, and a point support member made of a material that is harder than the sheet elastic body and undergoes plastic deformation under the load of the heavy article, the point support member being held in a position deviated from a center of the sheet elastic body. In this structure, at least three tip-resistant pads are arranged on the foundation with the point support members oriented inward of the foundation.

In one aspect of this embodiment, the structure further comprises at least three pressure plates each of which is interposed between one of the tip-resistant pads and the heavy article for compressing the sheet elastic body and the point support member to the same level.

In another aspect of this embodiment, each of the point support members is embedded in a corner of the sheet elastic body.

In a different aspect of this embodiment, each of the point support members is embedded in the sheet elastic body with a portion of the support member exposed above a surface of the sheet elastic body.

EFFECT OF THE INVENTION

According to the tip-resistant pad and the seismically isolated structure of the present invention, the point support member is held in an off-center position or a position deviated from the center of the sheet elastic member. As such, the total effective area of the sheet elastic members are increased by orienting the point support member inward of the foundation, thereby enhancing the ability of the pad and the structure to prevent the heavy article from tipping over or falling down.

BRIEF DESCRIPTION OF THE ATTACHED DRAWINGS

For a fuller understanding of the nature and objects of the present invention, reference should be made to the following detailed description and the accompanying drawings, in which:

FIG. 1 is a perspective exploded view of a gravestone structure using a plurality of tip-resistant pads according to one embodiment of the present invention;

FIG. 2A is a perspective view showing the tip-resistant pad of FIG. 1;

FIG. 2B is a perspective view showing an alternative tip-resistant pad similar to that shown in FIG. 2A but without the circular holder;

FIG. 3A is an exploded view of the tip-resistant pads and the gravestone structure of FIG. 1;

FIG. 3B is a front view of the tip-resistant pads of FIG. 1 in use to prevent the gravestone structure from tipping over;

FIG. 4 is a plan view of the tip-resistant pads arranged in certain orientation in the gravestone structure of FIG. 1;

FIG. 5A shows an alternate embodiment of the sheet elastic body of each of the tip-resistant pads shown in FIG. 1;

FIG. 5B shows another alternate embodiment of the sheet elastic body of each of the tip-resistant pads shown in FIG. 1;

FIG. 6 shows alternate embodiments of the point support member of each of the tip-resistant pads shown in FIG. 1;

FIG. 7 is a perspective view of a conventional tip-resistant pad; and

FIG. 8 is a plan view of four conventional tip-resistant pads of FIG. 7 as arranged in a gravestone structure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A gravestone structure that embodies the present invention will be described hereinafter with reference to the attached drawings. FIG. 1 shows a gravestone structure 1 that includes a foundation stone 2 set on the ground and a heavy article, such as a headstone 3, set on the foundation stone 2. Interposed between the foundation stone 2 and the headstone 3 are four tip-resistant pads 4. The gravestone structure 1 additionally includes four pressure plates 5 with each interposed between each pad 4 and the headstone 3. In the event of an earthquake, the four tip-resistant pads 4 are adapted to prevent the headstone 3 from tipping over or falling down.

As shown in FIG. 2A, each of the tip resistant pads 4 includes a circular sheet elastic body 6 with a corner or a lug, a spherical point support member 7, and an annular holder 8. The sheet elastic body 6 is formed in a transparent, flexible and elastic gel material having elasto-viscosity and provided with a corner or lug 6 a in a position deviated from, or eccentric relative to, the center of the elastic body 6. The point support member 7 is formed of a metal or resin harder than the gel elastic material and embedded in the corner 6 a of the sheet elastic body 6 via the holder 8. In addition, the support member 7 undergoes plastic deformation under the load of the headstone 3. Alternatively, as shown in FIG. 2B, the point support member 7 may be directly set in the gel elastic material without using the annular holder 8.

As shown in FIG. 3A, the diameter of each point support member 7 is larger than the thickness of the sheet elastic body 6, exposing a portion of the support member 7 above the top surface of the sheet elastic body 6 when the tip-resistance pad 4 is in its natural state. The sheet elastic body 6 is provided with adhesive layers 6 c and 6 b on the top and bottom surfaces thereof, respectively, such that in use, the bottom side adhesive layer 6 b adheres to the surface of the foundation stone 2 with the top side adhesive layer 6 b adhering to the pressure plate 5. As best shown in 3B, the pressure plate 5 is formed with a slightly larger surface than that of the sheet elastic body 6 and bonded to the bottom surface of the headstone 3 with an adhesive (not shown). Under the load of the headstone 3, the pressure plate 5 compresses the sheet elastic body 6 and the point support member 7 to the same height or level.

Turning now to FIG. 4, in order to render the gravestone structure 1 seismically isolated, four tip-resistant pads 4 are affixed to the top surface of the foundation stone 2 and a pressure plate 5 is bonded to each tip-resistant pad 4. Subsequently, the pads 4 and the pressure plates 5 are interposed between the foundation stone 2 and the headstone 3. During installation, the tip-resistant pads 4 are arranged on the foundation stone 2 with the point support members 7 oriented or pointing inward of the foundation stone 2. This ensures that most of the gel elastic material of each pad 4 is located in an outer region of the foundation stone 2 (i.e., the region of the foundation stone 2 outside of the square defined by connecting the point support members 7) since each of the point support members 7 is held in an eccentric or deviated position on the respective sheet elastic body 6.

As shown above, the seismically isolated gravestone structure 1 of the foregoing embodiment includes an enlarged effective area of the sheet elastic bodies 6 for enhanced vibration absorption, thereby making it more difficult for the headstone 3 to fall down. Moreover, since the point support members 7 are embedded in the corners 6 a of the transparent sheet elastic bodies 6 with their portions exposed above the top surfaces of the tip-resistant pads 4, the pads 4 can easily be affixed to the foundation stone 2 while ensuring the correct orientation of each pad 4. Furthermore, as each of the pressure plates 5 compresses the entire tip-resistant pad 4 uniformly to the same level, the seismically isolated structure is capable of uniformly absorbing vibrations in all directions and facilitates achievement of the verticality of the headstone 3.

It should be noted that the present invention is not limited to the foregoing embodiment and can still be carried out while changing, altering, or modifying the shapes of the sheet elastic bodies and/or the point support members and/or changing the use of the tip-resistant pads to suit particular applications as illustrated below.

-   -   (1) As shown in FIG. 5A, according to one embodiment of the         present invention, each sheet elastic body 16 may be formed in a         rectangular shape with a point support member 7 embedded in one         of the corners 16 a thereof.     -   (2) As shown in FIG. 5B, according to another embodiment of the         present invention, each sheet elastic body 26 may be formed in a         triangular shape with a point support member 7 embedded in one         of the corners 26 a thereof.     -   (3) With reference to FIG. 6, point support members 37 formed         in (a) a cone, (b) a triangular pyramid, (c) a cylinder, (d) a         hexahedron, (e) a dodecahedron, or (f) an icosahedron may be         used instead of the spherical support members 7.     -   (4) The tip-resistant pads shown in FIGS. 2 and 5 may be used         with stone lanterns, stone water basins, stone monuments, and         other stone structures. In addition, these pads may also be used         with wooden structures and steel structures that cannot or         should not be secured with anchor bolts.

Equivalents

It will thus be seen that the present invention efficiently attains the objects set forth above, among those made apparent from the preceding description. As other elements may be modified, altered, and changed without departing from the scope or spirit of the essential characteristics of the present invention, it is to be understood that the above embodiments are only an illustration and not restrictive in any sense. The scope or spirit of the present invention is limited only by the terms of the appended claims. 

1-12. (canceled)
 13. A manufacture comprising a tip-resistant pad for being interposed between a foundation and a heavy article to prevent said heavy article from tipping over due to an earthquake, said tip-resistant pad comprising a sheet elastic body made of a flexible material for absorbing vibrations of said heavy article, and a point support member made of a material that is harder than said sheet elastic body and that undergoes plastic deformation under a load from said heavy article, wherein said point support member is held in a position deviated from a center of said sheet elastic body.
 14. The manufacture of claim 13, wherein said point support member is embedded in a corner of said sheet elastic body.
 15. The manufacture of claim 14, wherein said point support member is embedded in said sheet elastic body with a portion of said support member exposed.
 16. The manufacture of claim 14, wherein said sheet elastic body comprises an adhesive layer on a top surface thereof and an adhesive layer on a bottom surface thereof
 17. The manufacture of claim 14, wherein said sheet elastic body comprises a transparent and elastic gel material.
 18. The manufacture of claim 17, wherein said sheet elastic body comprises an adhesive layer on a top surface thereof and an adhesive layer on a bottom surface thereof.
 19. The manufacture of claim 13, wherein said point support member is embedded in said sheet elastic body with a portion of said support member exposed.
 20. The manufacture of claim 19, wherein said sheet elastic body comprises a transparent and elastic gel material.
 21. The manufacture of claim 20, wherein said sheet elastic body comprises an adhesive layer on a top surface thereof and an adhesive layer on a bottom surface thereof.
 22. The manufacture of claim 19, wherein said sheet elastic body comprises an adhesive layer on a top surface thereof and an adhesive layer on a bottom surface thereof.
 23. The manufacture of claim 13, wherein said sheet elastic body comprises a transparent and elastic gel material.
 24. The manufacture of claim 23, wherein said sheet elastic body comprises an adhesive layer on a top surface thereof and an adhesive layer on a bottom surface thereof.
 25. The manufacture of claim 13, wherein said sheet elastic body comprises an adhesive layer on a top surface thereof and an adhesive layer on a bottom surface thereof
 26. An apparatus comprising a structure including a foundation, a heavy article, and a plurality of tip-resistant pads interposed between said foundation and said heavy article to prevent said heavy article from tipping over due to an earthquake, wherein each of said tip-resistant pads comprises a sheet elastic body made of a flexible material for absorbing vibrations of said heavy article, and a point support member made of a material that is harder than said sheet elastic body and that undergoes plastic deformation under a load from said heavy article, said point support member being held in a position deviated from a center of said sheet elastic body, wherein at least three of said tip-resistant pads are arranged on said foundation, wherein for each of said three tip-resistant pads, a point support member for said pad is closer to a center of said foundation than said center of said sheet elastic body.
 27. The apparatus of claim 26, further comprising at least three pressure plates, each of which is interposed between one of said tip-resistant pads and said heavy article, for compressing said sheet elastic body and said point support member to the same level.
 28. The apparatus of claim 26, wherein each of said point support members is embedded in a corner of said sheet elastic body.
 29. The apparatus of claim 26, wherein each of said point support members is embedded in said sheet elastic body with a portion of said support member exposed above a surface of said sheet elastic body. 